From 88389d6103a728e508f8090b71c0bfef0bc66f8f Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Tue, 4 May 2010 05:14:43 +0000
Subject: MFC r206264: When OOM searches for a process to kill, ignore the
 processes already killed by OOM. When killed process waits for a page
 allocation, try to satisfy the request as fast as possible.

---
 sys/vm/vm_fault.c   | 21 +++++++++++++++------
 sys/vm/vm_pageout.c |  4 ++--
 2 files changed, 17 insertions(+), 8 deletions(-)

(limited to 'sys/vm')

diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index 68057fb4f3fd..a8ff435f443d 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -217,7 +217,7 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
 	vm_object_t next_object;
 	vm_page_t marray[VM_FAULT_READ];
 	int hardfault;
-	int faultcount, ahead, behind;
+	int faultcount, ahead, behind, alloc_req;
 	struct faultstate fs;
 	struct vnode *vp;
 	int locked, error;
@@ -414,9 +414,14 @@ RetryFault:;
 
 			/*
 			 * Allocate a new page for this object/offset pair.
+			 *
+			 * Unlocked read of the p_flag is harmless. At
+			 * worst, the P_KILLED might be not observed
+			 * there, and allocation can fail, causing
+			 * restart and new reading of the p_flag.
 			 */
 			fs.m = NULL;
-			if (!vm_page_count_severe()) {
+			if (!vm_page_count_severe() || P_KILLED(curproc)) {
 #if VM_NRESERVLEVEL > 0
 				if ((fs.object->flags & OBJ_COLORED) == 0) {
 					fs.object->flags |= OBJ_COLORED;
@@ -424,10 +429,13 @@ RetryFault:;
 					    fs.pindex;
 				}
 #endif
+				alloc_req = P_KILLED(curproc) ?
+				    VM_ALLOC_SYSTEM : VM_ALLOC_NORMAL;
+				if (fs.object->type != OBJT_VNODE &&
+				    fs.object->backing_object == NULL)
+					alloc_req |= VM_ALLOC_ZERO;
 				fs.m = vm_page_alloc(fs.object, fs.pindex,
-				    (fs.object->type == OBJT_VNODE ||
-				     fs.object->backing_object != NULL) ?
-				    VM_ALLOC_NORMAL : VM_ALLOC_ZERO);
+				    alloc_req);
 			}
 			if (fs.m == NULL) {
 				unlock_and_deallocate(&fs);
@@ -452,7 +460,8 @@ readrest:
 			int reqpage = 0;
 			u_char behavior = vm_map_entry_behavior(fs.entry);
 
-			if (behavior == MAP_ENTRY_BEHAV_RANDOM) {
+			if (behavior == MAP_ENTRY_BEHAV_RANDOM ||
+			    P_KILLED(curproc)) {
 				ahead = 0;
 				behind = 0;
 			} else {
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 723b14d2175a..dc2b3b77d569 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -1206,10 +1206,10 @@ vm_pageout_oom(int shortage)
 		if (PROC_TRYLOCK(p) == 0)
 			continue;
 		/*
-		 * If this is a system or protected process, skip it.
+		 * If this is a system, protected or killed process, skip it.
 		 */
 		if ((p->p_flag & (P_INEXEC | P_PROTECTED | P_SYSTEM)) ||
-		    (p->p_pid == 1) ||
+		    (p->p_pid == 1) || P_KILLED(p) ||
 		    ((p->p_pid < 48) && (swap_pager_avail != 0))) {
 			PROC_UNLOCK(p);
 			continue;
-- 
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